• Bulletin of the Korean Mathematical Society
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• v.50 no.2
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• pp.543-558
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• 2013

Let ${\Gamma}$ be a graph which contains two vertices $a$, $b$ with the same link. For the case where the link has less than 3 vertices, we prove that if the right-angled Artin group A(${\Gamma}$) contains a hyperbolic surface subgroup, then A(${\Gamma}$-{a}) contains a hyperbolic surface subgroup. Moreover, we also show that the same result holds with certain restrictions for the case where the link has more than or equal to 3 vertices.

• Journal of Acupuncture Research
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• v.30 no.1
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• pp.1-11
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• 2013

Objectives : The 7-zone-diagnostic system is a device for predetermining bodily locations by measuring the energy of the living body. The purpose of this study is to examine correlations between gastroscopy results and zone-5 data from the 7-zone-diagnostic system. Methods : This study was carried out with data from gastroscopy procedures. It involved 115 patients who had been diagnosed with gastritis, esophagitis, or gastric ulcers. These patients were divided into three groups according to the different patterns of zone-5 factors AA, FL2 and FL1. Group A was made up of patients for whom the red bar graph of zone-5 was higher than the normal range for factor AA. Group B was made up of patients for whom the red bar graph of zone-5 was within the normal range for factor AA. Group C was made up of patients for whom the red bar graph of zone-5 was lower than the normal range for factor AA. Group D E and F were made up of same way as group A B and C for factor FL2. Group G H and I were made up of same way as group A B and C for factor FL1. After the collection of gastroscopy results and data on zone-5 from the 7-zone-diagnostic system, the data was analyzed statistically. Results : 1. Group D had a higher ratio of medication than group E, and this result was statistically significant. 2. Group D G had a higher ratio of medication than group E G and group E H, and this result was statistically significant. 3. Group G had a higher ratio of esophagitis than group H, and this result was statistically significant. 4. A Group B H had a higher ratio of esophagitis than group B G, group C G, and group C H, and this result was statistically significant. 5. The medication group had a high score on the function index than the non-medication group, and this result was statistically significant. Conclusions : This study suggests that there is a slight correlation between gastroscopy results and zone-5 data from the 7-zone-diagnostic system. The research resulted in significant data that are helpful for diagnosing digestive system problems through the use of the 7-zone-diagnostic system.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.5 no.3
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• pp.76-85
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• 2024

The purpose of this study is to propose a new method of analysis focusing on interconnections between species rather than traditional biodiversity analysis, which represents ecosystems in terms of species and individual counts such as species diversity and species richness. This new approach aims to enhance our understanding of ecosystem networks. Utilizing data from the 4th National Natural Environment Survey (2014-2018), the following eight taxonomic groups were targeted for our study: herbaceous plants, woody plants, butterflies, Passeriformes birds, mammals, reptiles & amphibians, freshwater fishes, and benthonic macroinvertebrates. A co-occurrence frequency analysis was conducted using nationwide data collected over five years. As a result, in all eight taxonomic groups, the degree value represented by a linear regression trend line showed a slope of 0.8 and the weighted degree value showed an exponential nonlinear curve trend line with a coefficient of determination (R²) exceeding 0.95. The average value of the clustering coefficient was also around 0.8, reminiscent of well-known social phenomena. Creating a combination set from the species list grouped by temporal information such as survey date and spatial information such as coordinates or grids is an easy approach to discern species distributed regionally and locally. Particularly, grouping by species or taxonomic groups to produce data such as co-occurrence frequency between survey points could allow us to discover spatial similarities based on species present. This analysis could overcome limitations of species data. Since there are no restrictions on time or space, data collected over a short period in a small area and long-term national-scale data can be analyzed through appropriate grouping. The co-occurrence frequency analysis enables us to measure how many species are associated with a single species and the frequency of associations among each species, which will greatly help us understand ecosystems that seem too complex to comprehend. Such connectivity data and graphs generated by the co-occurrence frequency analysis of species are expected to provide a wealth of information and insights not only to researchers, but also to those who observe, manage, and live within ecosystems.

• Journal of Korean Academy of Nursing
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• v.53 no.3
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• pp.359-369
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• 2023

Purpose: This study evaluated the internal structure (structural validity, internal consistency, and measurement invariance) of the Health-Related Quality of Life Instrument with Eight Items (HINT-8), developed to measure Korean people's health-related quality of life. Methods: A secondary analysis was conducted using data from the Korea National Health and Nutrition Examination Survey, involving 6,167 adults aged over 18 years. The structural validity of the HINT-8 was assessed using exploratory graph analysis and confirmatory factor analysis. Internal consistency and measurement invariance were analyzed using McDonald's omega (ω) and multigroup confirmatory factor analysis, respectively. Results: The HINT-8 had a single dimension and good internal consistency (ω =.804). The one-dimension HINT-8 exhibited matric invariance but not scalar invariance across sociodemographic groups (sex, age, education, and marital status). Further, it exhibited scalar or partial scalar invariance across medical condition groups (hypertension, diabetes, depressive symptoms, and cancer). Conclusion: The study finds that the HINT-8 demonstrated satisfactory structural validity and internal consistency, indicating its suitability for practice and research. However, the HINT-8 scores cannot be compared across different groups regarding sex, age, education, and marital status, as the interpretation varies within each sociodemographic category. Conversely, interpretation of the HINT-8 is consistent for individuals with and without hypertension, diabetes, depressive symptom, and cancer.

• Journal of Korean Society of Rural Planning
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• v.20 no.2
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• pp.11-22
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• 2014

In this study, the objectives are to provide rural experience tourism village business courses and development direction in between individual farmers and the village in base on rural development business of Hapjeon-village. The developmental process of a farm-stay village can be categorized into the period of six stages: 1) a conception stage 2) an adoption stage 3) a growth stage 4) an expansion stage 5) a stagnation stage 6) a recovery stage. Farm Stay Villages, Individual Farmhouses or Producer Groups can be placed in four different quadrant areas of a graph, depending on the pursuing direction and results of core values by having the X-axis for economic factors (public profits, individual profits) and by having the Y-axis for emotional factors (self-actualization, conflicts). The first quadrant area is designated for ideal individual farmhouses and producer groups for having achieved the status of economic self-reliant and high emotional satisfaction. The second quadrant is for ideal self-actualized communal villages having achieved the independent public interest and public profitable status. The third quadrant is reserved for villages experiencing communal conflicts and no economic self-reliant stagnant status. The fourth guardant area is allocated for individual farmhouses and producer groups having achieved self-reliant economic status, yet having communal conflicts. Using the aforementioned concept, the government shall design village development projects and prepare realistic and achievable goals and place them in as a systematic device in future projects.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1235-1242
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• 2019

While several machine learning technique has been implemented for Android malware categorization, there is still difficulty in analyzing due to overfitting problem and including of un-executable code, etc. In this paper, we introduce our implemented tool to address these problems. Tool is consists of approximately 1,500 lines of Java code, and perform Flow analysis on set of APIs, or on control flow graph. Our tool groups all the API by its relationship and only perform analysis on actually executing code. Using our tool, we grouped 39032 APIs into 4972 groups, and 12123 groups with result of including class names. We collected 7,000 APKs from 7 families and evaluated our feature reduction technique, and we also reduced features again with selecting APIs that have frequency more than 20%. We finally reduced features to 263-numbers of feature for our collected APKs.

• Journal of The Korean Association For Science Education
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• v.43 no.3
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• pp.225-236
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• 2023

This study investigated the characteristics of pre-service elementary teachers' TPACK in science lesson planning using VR/AR content based on epistemic network analysis (ENA). Seven TPACK coding elements were derived inductively based on the existing TPACK framework. Then, the pre-service elementary teachers' discourse in science lesson planning was coded according to the seven TPACK coding elements and analyzed using the ENA Web Tool. The discourses of the two groups were analyzed and compared, and the differences between the two groups, which the researchers analyzed qualitatively, were clearly shown on the ENA graph. Based on these findings, the researchers argued that the ENA method is a useful research tool for analyzing the complex interactions of technology knowledge (TK), content knowledge (CK), and pedagogical knowledge (PK), which is different from previous TPACK research. Also, the researchers discussed the implications for the TPACK competency development of pre-service teachers by comparing the characteristics of the two groups' discourse.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.320-329
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• 2023

Background: Oral frailty has garnered considerable interest following its identification as a risk factor for physical frailty. The Korean oral frailty diagnosis criteria have emphasized the need for extensive research on oral frailty diagnostic items and interventions. Our study performed an in-depth analysis of the tongue-palate pressure patterns in healthy community-dwelling older adults. Methods: Of the 217 older adults aged ≥60 years who visited a senior center in Wonju, 205 participants who completed tongue pressure measurement were included in the final analysis. Pressure changes over time were recorded by instructing the participants to press their tongue against the hard palate with for 7 seconds per cycle. The participants were divided into the normal and abnormal tongue pressure (NTP and ATP, respectively) groups based on whether they achieved the target tongue pressure at least once; tongue pressure patterns were compared between the groups. Furthermore, the average time taken to achieve the standard tongue pressure value was calculated for the participants in the NTP group and used to evaluate the decrease in tongue pressure in the ATP group. Results: Among the 205 participants, 40.5% had ATP. The tongue pressure graph revealed a gentle and consistent incline that was maintained even after achieving standard tongue pressure in the NTP group. The graph was more extreme in the ATP group, and the changes in the pressure type varied across individuals; the tongue pressure was only 48.4%, 40.7%, 31.9%, and 22.6% of the NTP in the participants in their 60s, 70s, 80s, and ≥90s, respectively (p<0.05). Conclusion: Tongue pressure weakness was observed in 40.5% of the healthy community-dwelling older adults. Furthermore, ATP graphs were observed in the patients with tongue pressure weakness. Thus, activities improving the oral function in community-dwelling older adults and systematic oral rehabilitation programs should be devised to promote normal swallowing.

• The Korean Journal of Physiology
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• v.10 no.2
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• pp.39-45
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• 1976

This study was conducted to see whether the hippocampectomy exerted facilitatory influence upon gastric ulceration in animals, and if so, whether the effect of hippocampectomy could be suppressed by adrenalectomy. 107 male rats were divided into 5 groups: rats that had over 90% of their hippocampal tissue removed through an opening on each side of the cerebral cortex(hippocampal group, N=21), rats that received bilateral adrenalectomy(adrenal group, N=29), rats that received adrenalectomy as well as hippocampectomy(hippocampo-adrenal group, N=10), rats that received damage to each side of the cortex over the hippocampus(cortical control group, N=20), and rats that had solely their head skin incised(normal control group, N=27). All rats were kept without restraint or food deprivation until on the 25th day after surgery, the stomach of each rat was inflated with 7ml of physiological saline and then removed under deep anesthesia. The mucosal surface was sketched under dissecting microscope, and enlarged photographs$(4{\times})$ were taken. The percentage of animals developing gastric ulcer in each animal group was calculated, the number of ulcer in each stomach was counted, and the total area of ulceration per stomach was measured on the Photograph with the aid of superimposed graph paper and expressed as permillage of total area of the glandular mucosa. Results obtained were as follows: 1. The percentage of animals developing gastric ulcer was significantly larger in the hippocampal group than they were in the hippocampo-adrenal, the adrenal, the cortical, and the normal control groups. 2. The mean number of ulcer per stomach was significantly larger in the hippocampal group than they were in the adrenal, the cortical control, and the normal control groups, while no significant difference existed between the hippocampal and the hippocampo-adrenal groups. 3. Total area of ulcer per stomach was significantly larger in the hippocampal group than they were in the cortical control and the normal control groups, but no significant differ-ence existed among the hippocampal, the adrenal, and the hippocampo·adrenal groups. 4. All measured values of the adrenal group were not significantly different from those of the hippocampo-adrenal, the cortical control, and the normal control groups. It is inferred from the above results that the hippocampus exerts an inhibitory influence upon gastric ulceration and that the hippocampal influence is mediated only partly through suppression of pituitary·adrenal activity.

• Journal of Intelligence and Information Systems
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• v.27 no.4
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• pp.73-95
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• 2021

This study uses Node2vec graph embedding method and Light GBM link prediction to explore undeveloped export candidate countries in Korea's food and beverage industry. Node2vec is the method that improves the limit of the structural equivalence representation of the network, which is known to be relatively weak compared to the existing link prediction method based on the number of common neighbors of the network. Therefore, the method is known to show excellent performance in both community detection and structural equivalence of the network. The vector value obtained by embedding the network in this way operates under the condition of a constant length from an arbitrarily designated starting point node. Therefore, it has the advantage that it is easy to apply the sequence of nodes as an input value to the model for downstream tasks such as Logistic Regression, Support Vector Machine, and Random Forest. Based on these features of the Node2vec graph embedding method, this study applied the above method to the international trade information of the Korean food and beverage industry. Through this, we intend to contribute to creating the effect of extensive margin diversification in Korea in the global value chain relationship of the industry. The optimal predictive model derived from the results of this study recorded a precision of 0.95 and a recall of 0.79, and an F1 score of 0.86, showing excellent performance. This performance was shown to be superior to that of the binary classifier based on Logistic Regression set as the baseline model. In the baseline model, a precision of 0.95 and a recall of 0.73 were recorded, and an F1 score of 0.83 was recorded. In addition, the light GBM-based optimal prediction model derived from this study showed superior performance than the link prediction model of previous studies, which is set as a benchmarking model in this study. The predictive model of the previous study recorded only a recall rate of 0.75, but the proposed model of this study showed better performance which recall rate is 0.79. The difference in the performance of the prediction results between benchmarking model and this study model is due to the model learning strategy. In this study, groups were classified by the trade value scale, and prediction models were trained differently for these groups. Specific methods are (1) a method of randomly masking and learning a model for all trades without setting specific conditions for trade value, (2) arbitrarily masking a part of the trades with an average trade value or higher and using the model method, and (3) a method of arbitrarily masking some of the trades with the top 25% or higher trade value and learning the model. As a result of the experiment, it was confirmed that the performance of the model trained by randomly masking some of the trades with the above-average trade value in this method was the best and appeared stably. It was found that most of the results of potential export candidates for Korea derived through the above model appeared appropriate through additional investigation. Combining the above, this study could suggest the practical utility of the link prediction method applying Node2vec and Light GBM. In addition, useful implications could be derived for weight update strategies that can perform better link prediction while training the model. On the other hand, this study also has policy utility because it is applied to trade transactions that have not been performed much in the research related to link prediction based on graph embedding. The results of this study support a rapid response to changes in the global value chain such as the recent US-China trade conflict or Japan's export regulations, and I think that it has sufficient usefulness as a tool for policy decision-making.